The first day walking the Camino Francis, one of the popular routes to Santiago de Compostela in Spain, involves walking through the Pyrenees Mountains. St Jean Pied de Port to Roncesvalles 24km, and is said to take 7 to 9 hours. We have made this trip twice now, our first days were both days were were at least 8 hours on the road.
During the day we climbed from St Jean Pied de Port at 200 metres above sea level to just above 1,400 meters then descend steeply back down again into Roncesvalles at 900 metres, which can be hard going on your knees and shins. Pack a lunch, while there is often a coffee truck on the road the options for food and water are limited.